Railway track circuit apparatus



Oct. 15, 1935. OHAGAN 2,017,546

RAILWAY TRACK CIRCUIT APPARATUS Filed July 1'7, 1934 -L F F- -l g r x P "'7' F .INVENTOR Bernard L. Oilagazz BY Q/ Q/IMJ/ I HIS ATTORNEY Patented Oct. 15, 1935 STTES PATENT OFFICE RAILWAY TRACK CIRCUIT APPARATUS Bernard E. OHagan, Swissvale, Pa., assignorto The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application July 17, 1934, Serial No. 735,576

22 Claims.

5 has a high degree of shunting sensitivity.

I will describe two forms of track circuit apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view illustrating one form of track circuit apparatus embodying my invention applied tothe control of a highway crossing signal. Fig. 2 is a diagrammatic view showing another form of track circuit apparatus embodying my invention.

Similar reference characters refer to similar parts in both views.

Referring first to Fig. 1, the reference characters l and I designate the track rails of a stretch of railway track over which trafiic normally moves in both directions. The rails I and I are divided, by means of insulated joints 2, to form two adjacent track sections AB and BC, and each of these track sections is provided, as usual, with a source of track circuit current, here shown as a battery 3, which battery is connected across the rails of the associated section in series with the usual resistor 4 at the end farthest away from the point B.

The reference character R designates a track relay comprising three parallel cores 5, 6 and 1, two of which, 5 and 1, are connected together at their upper ends by a backstrap 8, and the remaining one of which, 5, is spaced from the backstrap 8 by an air gap 9. The core 5 is provided with an operating winding 5 which is connected with the rails of section AB adjacent the point B, and the core I is similarly provided with an operating winding l which is connected with the rails of section B-C adjacent the point B. A tractive armature i5 is pivotally supported directly below the core 6 at point H for swinging movement toward and away from the core 5, and a similar tractive armature I2 is similarly pivotally supported directly below the core 6 for swinging movement toward and away from the core 7. The armature I0 is biased by gravity to an open position in which it is swung away from the core 5, and carries a contact finger is which, when the armature is swung toward the core 5, as shown in the drawing, engages a fixed contact member l3 to close a contact i3i3 The armature I2 is similarly biased by gravity to an open position in which it is swung away from the core I, and carries a contact finger M which, when this armature is swung toward the core I, engages a fixed contact member I l to close a contact M-M The sections AB and BC are preferably of approximately equal lengths, and the parts are so arranged and are so proportioned that when these sections are bothunoccupied, the currents which are supplied to the windings 5 and l will set up substantially equal fluxes in the associated cores in such directions as to cause the corre- 5 spending ends of the cores to have the same polarity. It follows, therefore, that when sections AB and B-C are both unoccupied, assuming that the upper ends of the cores 5 and l are north poles, the flux set up in the core 5 by the winding 5 will flow from the upper end of this core through the left-hand half of backstrap 8, air gap 9, core 6, the air gap between core 6 and armature I0, armature l0, and the air gap between armature l0 and core 5 to the lower end of core 5; while the flux set up in core I by winding 1* will flow from' the upper end of this core through the right-hand half of backstrap 8, air gap 9, core 6, the air gap between core 6 and armature l 2, armature l2, and the air gap between armature l2 and core I to the lower end of core I. The parts are further so proportioned that when the sections AB and 3-0 are both unoccupied, the fluxes set up in the cores 5 and l by the currents supplied to the windings 5 and l willbe of such magnitude as to cause the armatures l0 and I2 to swing toward the associated cores, and close the associated contacts I3-l3 and l4-l4 I will now assume that a train moving from left to right traverses the stretch of track shown in the drawing. When the train enters section AB, the shunt formed by the wheels and axles of the train will cause a considerable reduction in the current which is supplied to winding 5 and hence in the flux which is set up in core 5 due to winding 5 and as a result, a part of the flux due to winding I which previously flowed through core 6 will now attempt to flow through the parallel path formed by core 5, thus causing the reluctance of this core to increase. This increase in reluctance in core 5 in combination with the natural decrease in flux due to the reduced current in winding 5 produces a resultant flux which is considerably lowerthan would be the case if the winding were not provided. It 45 will be seen, therefore, that with the relay R constructed in the manner described, the armature ll! willrelease on a much poorer train shunt than would otherwise be the case.

When the train enters section B-C, the train shunt will decrease the current flowing in winding i and hence the flux set up in core 1 by this winding, and as long as any part of the train still occupies section AB, the armature I2 will tend to release in the same manner as track relays of the usual type having only one winding. However, if the train shunt is so poor that the armature l2 fails to release while any part of the train is still in section AB, as soon as the train has fully entered section B-C, the train 60 shunt will then be removed from the winding 5 and this winding will become energized to its full value and will cause armature I to pick up, whereupon a part of the flux due to winding ii will tend to thread core I and will act to decrease the fiux in this core thus causing the armature IE to release in the same manner that the armature it released when the train entered section A-B. When the train has fully passed out of section B-C, armature I2 will pick up and the parts will then be restored to the positions shown.

When a train traverses the stretch of track shown in the drawing from right to left, the operation of relay R will be exactly the reverse of that just described, and it is believed that this operation will be readily understood from the foregoing description and from an inspection of the drawing without further detailed description.

It should be pointed out that with'the relay R constructed in the manner described, when the current in either of the windings 5 and 1 is reduced due to a train shunt, the amount of flux which threads the associated core due to the cur- .rent which is then flowing in the other winding depends upon the ratio of the reluctance of the air gap 9 to the armature air gaps, and it follows that by varying this ratio different degrees of shunting sensitivity can be obtained.

As is well known in the railway signaling art, the ballast leakage resistance of a track section, that is, the resistance from rail to rail through the ties and ballast, varies through wide limits depending upon weather conditions, the resistance being comparatively low when the ballast is wet and comparatively high when the ballast is dry. With a relay constructed and arranged in accordance with my invention, if the two track sections are of approximately equal lengths, the energization of the two windings 5 and l of the relay will vary with this variation in ballast resistance at approximately the same rate, since when the ballast resistance of either track circuit is low, the ballast resistance of the other track circuit will also be low, and, when the ballast resistance of either track circuit is high, the ballast resistance of the other track circuit will likewise be high. It follows, therefore, that the proper balance of fluxes set up in the core structure of the relay by the currents flowing in the two windings 5 and I will be obtained throughout the whole range of weather conditions.

The relay R may be employed for any desired purpose but as here shown it is utilized to control an interlocking relay L which, in turn, controls a signal S. The signal S is disposed adjacent a highway H which intersects the stretch of track shown in the drawing adjacent the point B, and is provided for the purpose of warning users of the highway that a train is approaching the highway. 7

The interlocking relay L is of the usual and well-known type, and comprises a magnet I5 which controls a back contact lfi and a magnet I 6 which controls a back contact Hi. If magnet !5 becomes deenergized when magnet I6 is energized, contact w will become closed, but if magnet i?) becomes deenergized when magnet I6 is deenergized, contact I5 will remain open. Similarly, if magnet It becomes deenergized when magnet 55 is energized, contact it will become closed; but if magnet l6 becomes deenergized when magnet 85 is deenergized, contact l6 will remain open. One form of, relay of the type described is illustrated in Letters Patent of the United States No. 799,452, granted to W. W. Coleman, on September 12, 1905.

Magnet if? of interlocking relay L is provided with a circuit which includes a suitable source of current here shown as a battery D and con- 5 tact l3i3= of relay R. Magnet I6 of interlocking relay L is provided with a similar circuit which includes battery D and contact M-Hl of relay R.

Signal S may be of any suit-able type, but as 10 shown this signal is an electric bell. This signal is provided with a circuit which includes battery D and. the contacts w and It of relay L connected in parallel, and it will be apparent, therefore, that this signal will operate whenever either 15 contact i5 or E5 of relay L is closed.

The operation of the apparatus as a whole is as follows: When a train moving from right to left enters section A-B, armature ID of relay R will release in the manner previously described, and the releasing of this armature will interrupt the circuit for armature iii of interlocking relay L, thus causing contact l5 of relay L to become closed. When contact l5 becomes closed, bell Swill start to ring, thereby warning users of the highway that a train is approaching the highway. When the train enters section B-C, armature l2 of relay'L will drop which will deenergize magnet iii of relay L. Since magnet 15 of relay L is then deenergized, however, contact- 25 will remain open under these conditions. When the train has fully entered section B-C, armature ill of relay R will pick up and will complete the circuit for magnet i5, whereupon contact l5 will open and will deenergize bell S. When the train departs from section BC, armature E2 of relay R will pick up and will complete the circuit for magnet l6 of relay L, and when this happens all parts will be restored to the positions shown. 40

The operation of the apparatus as a whole when the train traverses the stretch of track shown in the drawing from right to left will be obvious from the foregoing and from an inspection of the drawing without further description.

Referring now to the form of the apparatus illustrated in Fig. 2, as here shown the rails I and. I of a stretch of track over which trafiic normally moves in the direction indicated by the arrow are divided by insulated joints 2 to form a plurality of track sections, such as E-F and FG. Each track section is provided with a track battery 3 which is connected across the rails adjacent the exit end of the section in series with the usual current resistor 4. Section FG is also provided with a track relay R which track relay is similar to the track relay R shown in Fig. 1. The winding l of track relay R is connected across the rails of section FG in series with the contact l3-l3 of the relay, while the winding 5 of this track relay is connected with the battery 3 for section EF in series with a resistor H. The winding 5 of relay R also has one terminal connected with the rail l of section E-F andthe other terminal connected with an auxiliary conductor !8 which is preferably located midway between the rails I and l of section EF. The conductor I3 may be of any suitable type 'and may have any desired length. One form of conductor which may be used is a section of ordinary track rail spiked to the ties in the customary manner.

With the apparatus arranged as shown in Fig. 2, the ballast leakage resistance of section FG is in multiple with winding I of relay R and it will be apparent, therefore, that if the ballast resistance of this section decreases, the voltage applied to winding I will decrease due both. to the shunt,- ing effect of the ballast resistance, and also tothe fact that any decrease in the ballast resistance increases the load on battery 3 thereby causing an increased potential drop in resistor 4, and hence causing a decreased potential to be applied to the rails of the section. However, as the ballast resistance of section F--G decreases, theresistance between the conductor l8 and the rail I of this section also decreases, and since the resistance between conductor i8 and rail" l is connected in series with the resistor l 1 across the resistor 4, the total efiective resistance between the battery 3 and the rails l and I will decrease as the ballast resistance decreases, thus tending to lessen to a certain extent the drop between the battery and the rails due to the increased load on. the track circuit, and hence tending to maintain the energization of winding 'l at a more constant value than would be the case if the conductor l8 and resistor I! were not provided. This is desirable ior reasons which are well understood.

As the ballast resistance between the rails of section FG, and between conductor l3 associated with this section and the rail l of this section decreases, the ballast resistance between theconductor i8 associated with section E-F and the rail l of section E-F also decreases. As will readily be understood from an inspection of the drawing, any decrease in the ballast resistance between conductor i8 associated with section EF and rail l of this section will cause an increased current to flow through resistor H which will cause the potential drop across this resistor to increase, thus decreasing the energization of winding 5. This change in the energization of winding 5 is accompanied by simultaneous changes in the various possible circuits through which the current from battery 3 may flow, as will be apparent from the preceding paragraph and an analysis of the network formed by these circuits, and these changes will have some effect on the resultant energization of winding 5 However, by properly proportioning the parts, the changes in the energization of. winding 5 due to the change in ballast resistance between the conductor l8 associated with section EF and rail I of this section may be made to vary in substantially the same manner as the changes in the energization of winding i= due to the changes in ballast resistance of section F-G, and it follows, therefore, that with the track circuit apparatus arranged as shown in Fig. 2, the proper balance of fluxes in the cores 5 and I necessary for the satisfactory operation of the relay may be maintained under all conditions of weather even though the adjacent sections have different lengths.

The operation, as a whole, of the apparatus shown in Fig. 2 is as follows: When sections EF and F-G are both unoccupied, windings 5 and l are both energized, and armatures l and 12 are both picked up so that contacts l3l3 and hii M are both closed. When a train enters. section EF, the energization of winding is substantially unaffected, and no change occurs in the condition of relay R When, however, the train enters section F-G, the train shunt will decrease the energization of winding l thus causing the flux in core '3 to decrease due both to the decrease in energization of winding 1, and also to the increased reluctance of core 1 caused by the tendency of the flux set up in core 5 by winding 5 to thread this core. Armature l2 will,

therefore, release and open contact l4-M=-. When the train departs from section FG, winding l will again become energized and will cause armature l2 to pick up and close contact I4l4 When armature I2 picks up, all parts will be re- 5 Although I have herein shown and described 16-v only two forms of railway track circuit apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of 20 my invention.

Having thus described my invention, what I claim is:

1. In combination, two sections of railway track each provided with a source of track circuit current, a track relay having two magnetic circuits each including a common magnetic path, two armatures, one included in each magnetic circuit, and two windings one associated with each magnetic circuit and each connected to a difierent one of said track sections.

2. In combination, two sections of railway track each provided with a source of track circuit current, a track relay comprisingv two magnetic circuits each including a separate pivoted armature 3 and a common magnetic path having a relatively high reluctance, and two windings one associated with each magnetic circuit and each connected with a different one of said track sections.

3. In combination, two sections of railway track 40 each provided with a source of track circuit current, and a track relay comprising two magnetic circuits each including a separate pivoted armature and a common magnetic path having a relatively high reluctance, and two windings one associated with each magnetic circuit and each connected with a different one of said track sections in such manner that the resultant currents supplied to said windingsv will set up fluxes in said two magnetic circuits which traverse the common path in the same direction.

4. A relay comprising two parallel cores connected together at their upper ends by a backstrap and each provided with an energizing winding, a third parallel core separated at its upper end from said backstrap by an air gap, and two armatures each pivotally supported directly below said third core and each coacting with a different one of the remaining cores.

5. A relay comprising two parallel cores connected together at their upper ends by a backstrap and each provided with an energizing winding, a third parallel core separated at its upper end from said backstrap by an air gap, and two armatures each pivotally supported di- 5 rectly below said third core and each arranged to swing toward and away from a. different one of the remaining cores. 7

6. A relay comprising two parallel cores connected together at their upper ends by a backstrap and each provided with an energizing winding, a third parallel core separated at its upper end from said backstrap by an air gap, and two pivoted armatures, one cooperating with the third core and one of the other cores and the other 75.

25 all 55 arated at its upper end from said backs-trap by cooperating with the third core and the remaining core.

'7. In combination, two sections of railway track each provided with a'source of track circuit current, a track relay comprising a first and a second parallel core connected together at their upper ends by a backstrap, a winding on the first core connected with the one section of track and another winding on the second core connected with the other section of track, a third core separated at its upper end from said backstrap by an air gap, and two pivoted armatures one coacting with the first and third cores and the other coacting with the second and third cores.

8. In combination, two sections of railway track each provided with a source of track circuit current, a track relay comprising a first and a second parallel core connected together at their upper ends by a backstrap, awinding on the first core connected with the one sect-ion of track and another winding on the second core connected with the other section of track, a third core separated at its upper end from said backstrap by an air gap, and two pivoted armatures one coacting with the first and third cores and the other coacting with the second and third cores, the parts being so proportioned that when said sections are both unoccupied, the resultant fluxes set up in said first and second cores by the currents supplied to the associated windings will have equal magnitudes and will cause the corresponding ends oi the cores to have the same polarity.

9. In combination, two sections of railway track each provided with a source of track circuit current, a track relay comprising a first and a second parallel core connected together at their upper ends by a backstrap, a winding on the first core connected with the one section of track and another winding on the second core connected with the other section of track, a thirdcore separated at its upper end from said backstrap by an air gap, and two armatures each pivotally supported directly below said third core and each arranged to swing toward and away from a different one of said first and second cores.

10. In combination, two adjacent sections of railway track of substantially equal lengths each provided with a source of track circuit current,

a track relay comprising a first and a second parallel core connected together at their upper ends by a backstrap, a winding on the first core connected with the one section of track and another winding on the second core connected with the other section of track, a third core sepan air gap, and two pivoted armatures one coacting with the first and third cores and the other coacting with the second and third cores.

11. In combination, two'adjacent sections of railway track of substantially equal lengths each provided with a source of track circuit current, a track relay comprising a first and a second parallel core connected together at their upper ends by a backstrap, a winding on the first core connected with the one section of track and another Winding on the second core connected with the other section of track, a third core separated at its upper end from said backstrap by an air .gap, and two pivoted armatures one coacting with the first andthird cores and the other coacting with the second and third cores, the parts being so proportioned that when said sections are both unoccupied, the resultant fluxes set up in said first and secondcores by the currents supplied to the associated windings will have equal magnitudes and will cause the corresponding ends of the cores to have the same polarity.

12. In combination, two sections of railway track each provided with a source 01' track cir- 5 cuit current, a track relay comprising two magnetic circuits each including a separate pivoted armature and a common magnetic path, a winding on the one magnetic circuit connected with one track section, and a winding on the other magnetic circuit having its energization controlled in accordance with the ballast resistance of the other section.

13. In combination, two sections of railway track each provided with a source of track cirsuit current, a' track relay comprising two magnetic circuits each including a separate pivoted armature and a common magnetic path, a winding on the one magnetic circuit connected with one track section, and a winding on the other magnetic circuit having its energization controlled in accordance with the ballast resistance of the other section, the parts being so proportioned that the fluxes set up in both magnetic circuits by the current in the associated windings will thread the common magnetic path in the same direction and will have substantially equal magnitude under all conditions of ballast resistance.

14. In combination, two sections of railway track, a relay comprising two cores connected together at one end by a backstrap, a third core separated at one end from said backstrap by an air gap, two pivoted armatures one cooperating with the third core and one of the other cores and the other cooperating with the third core and the other core, a first energizing winding on the one core connected with the rails of one track section, and a second winding on the other core having its energization varied in accordance with the variations in ballast resistance of the other section, the parts being so proportioned that the fluxes set up in said one and said other core by the currents supplied to the associated windings will thread the third core in the same direction and will have substantially the same magnitudes under all conditions of ballast resistance.

15. In combination, two sections of railway track, a relay comprising two cores connected together at one end by a backstrap, a third core separated at one end from said backstrap by an air gap, two pivoted armatures one cooperating with the third core and one of the other cores and the other cooperating with the third core and the other core, a first energizing winding on the one core connected with the rails of one track section, a second winding on the other core, means for energizing said second winding in such manner that the flux set up in said other core will thread said third core in the same direction as the flux set up in said one core by the current supplied to said one winding and will have substantially the same magnitude as the flux set up in said one core under all conditions of ballast resistance.

16. In combination, two sections of railway track, two auxiliary conductors one in contact with the ballast of each section, a battery connected with the rails of eachsection in series with a current limiting resistance, a resistor for each section having one terminal connected with the terminal of the associated current limiting resistance which i is connected to the associated battery and having the other terminal connected with said auxiliary conductor, a relay comprising two cores connected together at one end by a backstrap, a third core separated at one end from said backstrap by an air gap, two pivoted armatures one cooperating with the third core and one of the other cores and the other cooperating with the third core and the remaining core, a first energizing winding on said one core connected With the rails of said one track section and a second winding on the said remaining core connected with the battery for the other section in series with the resistor for said other section.

1'7. In combination, two sections of railway track, two auxiliary conductors one in contact with the ballast of each section, a battery connected with the rails of each section in series with a current limiting resistance, a resistor for each section having one terminal connected with the terminal of the associated current limiting resistance which is connected to the associated battery and having the other terminal connected with said auxiliary conductor, a relay comprising two cores connected together at one end by a backstrap, a third core separated at one end from said backstrap by an air gap, two pivoted armatures one cooperating with the third core and one with the other cores and the other cooperating with the third core and the remaining core, a first energizing winding on said one core connected with the rails and one track section, and a second winding on said remaining core connected with the battery for the other section in series with the resistor for said other section, the parts being so proportioned that the currents supplied to said windings will set up fluxes in the associated cores which thread the third core in the same direction and which have substantially the same magnitude under all conditions of ballast.

18. In combination, two sections of railway track, two auxiliary conductors one in contact with the ballast of each section, a battery connected with the rails of each section in series with a current limiting resistance, a resistor for each section having one terminal connected with the terminal of the associated current limiting resistance which is connected to the associated battery and having the other terminal connected with said auxiliary conductor, a relay comprising two cores connected together at one end by a backstrap, a third core separated at one end from said backstrap by an air gap, two pivoted armatures one cooperating with the third core and one of the other cores and the other cooperating with said third core and said remaining core, a contact controlled by said other armature, a first energizing winding on said one core connected with the rails of said one track section over said contact, and a second winding on said remaining core connected with the battery for the other section in series with the resistor for said other section, the parts being so proportioned that the currents supplied to said windings will set up fluxes in the associated cores which thread the third core in the same direction and which have substantially the same magnitude under all conditions of ballast.

19. In combination, a stretch of railway track divided into two adjacent sections each of which is provided with a source of track circuit current, a track relay having two magnetic circuits each including a common magnetic path, two armatures one included in each magnetic circuit, two windings one associated with each magnetic circuit and each connected to a different one of said track sections, an interlocking relay having one magnet controlled by one armature of said track relay and the other magnet controlled by the other armature of said track relay, and an electroresponsive device controlled by said interlocking 5 relay.

20. In combination, a stretch of railway track divided into two adjacent sections each of which is provided with a source oi track circuit current,

a track relay having two magnetic circuits each 10 including a common magnetic path, two armatures one included in each magnetic circuit, two windings one associated with each magnetic circuit and each connected to a different one of said track sections, an interlocking relay having one 1.5 magnet controlled by one armature of said track relay and the other magnet controlled by the other armature of said track relay, a highway intersecting said stretch at substantially the junction of said two track sections, and a high- 20 way crossing signal located at the intersection of said railway track and said highway and controlled by said interlocking relay.

21. In combination, a stretch of railway track divided into two adjacent sections of substantial- 25 ly equal lengths, a source of track circuit current connected with the rails of each section, a track relay comprising a first and a second parallel core connected together at their upper ends by a backstrap, a. winding on the first core connected with 30 the one section of track and another winding on the second core connected with the. other section of track, a third core separated at its upper end from said backstrap by an air gap, two pivoted armatures one coacting with the first and third 35 cores and the other coacting with the second and third cores, an interlocking relay having one magnet controlled by one armature of said track relay and the other magnet controlled by the other armature of said track relay, a highway 40 intersecting said stretch at substantially the junction of said two track sections, and a highway crossing signal located at the intersection of said railway track and said. highway and controlled by said interlocking relay. 45

22. In combination, a stretch of railway track divided into two adjacent sections of substantially equal lengths, a source of track circuit current connected with the rails of each section, a track relay comprising a first and a second paral- 50 lel core connected together at their upper ends by a backstrap, a winding on the first core connected with the one section of track and another winding on the second core connected with the other section of track, a third core separated at 55 its upper end from said backstrap by an air gap, two pivoted armatures one coacting with the first and third cores and the other coacting with the second and third cores, the parts being so proportioned that when said sections are both unoccu- 60 pied the resultant fluxes set up in said first and second cores by the currents supplied to the associated windings will have equal magnitudes and will cause the corresponding ends of the cores to have the same polarity, an interlocking re- 65 lay having one magnet controlled by one armature of said track relay and the other magnet controlled by the other armature of said track relay, a highway intersecting said stretch at substantially the junction of said two track sections, 70 and a highway crossing signal locatedat the intersection of said railway track and said highway and controlled by said interlocking relay.

BERNARD E. OHAGAN. 75 

